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Nov 13, 2019, 05:49 PM
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Pattern_is_fun's Avatar
Here’s the specs on the Zippy 4500 40c 6S - not necessarily recommending but it’s worked well for me.

Specs:
Capacity: 4500 mAh
Cell Count: 6
Voltage: 22.2V
Constant Discharge: 40C
Peak Discharge: 80C
Wh: 99.90
Battery Size: 157x45x52mm
Approx. Weight: 725
Pack Resistance: 19mΩ
Charge Plug: JST-XH-24
Discharge Plug: XT90

Amazon has this motor.. compare weights to other motors.
Last edited by Pattern_is_fun; Nov 13, 2019 at 06:12 PM.
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Nov 13, 2019, 06:29 PM
Registered User
As I mentioned, the issue is my location. The motor is not available in the UK, from various outlets.
Dec 14, 2019, 06:45 AM
Registered User
Quote:
Originally Posted by Pattern_is_fun
Here’s the specs on the Zippy 4500 40c 6S - not necessarily recommending but it’s worked well for me.

Specs:
Capacity: 4500 mAh
Cell Count: 6
Voltage: 22.2V
Constant Discharge: 40C
Peak Discharge: 80C
Wh: 99.90
Battery Size: 157x45x52mm
Approx. Weight: 725
Pack Resistance: 19mΩ
Charge Plug: JST-XH-24
Discharge Plug: XT90

Amazon has this motor.. compare weights to other motors.
Hi Scott,

Is this the fms 550kv motor you would recommend for maximum power to weight ratio of the model? Or more just lightest to keep wing loading minimum?

I am coming from a foam Olympus. I really like the thrust to weight ratio of Olympus. I know I can't match it here but I want to build to Max thrust to weight ratio on 6S even if it means short flights on order of 5-6 minutes.

I don't plan to seriously compete but I do practice a lot of agressive manuevers. KE loop and Vertical KE figure 8 are some of my favorites along with point rolls on a vertical upline from takeoff.

Thoughts?

Thanks

Andrew
Dec 17, 2019, 09:06 PM
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Pattern_is_fun's Avatar
Hey Andrew.

I too flew the Olympus for a few flights. I then went to the Angel 50 and then to the Mythos. I don’t know if the FMS 550kv will give you the ‘max’ Power to weight but trust me, it’s a great fit for the plane - keeping the wind loading very light. I posted throttle curves here somewhere which will be a good starting point. This assumes you will fly the horizontal speed at 1/2 throttle and EASE into any upline not pushing the throttle quickly. Strive for constant speed with the power off downline speed dictating the baseline horizontal speed. Run a 16x10e with the FMS ESC and the combo is great.

There are many more expensive motor / ESC combinations out there but in my 3 years flying competition with this motor combo you will not be disappointed. Take note I use one elevator servo located at the back of the canopy. This allows for a lighter motor (as well as less tail momentum in snaps) as I don’t have to compensate for rear servo weight. Be careful here. Plan accordingly.

I fly the masters sequence in 7 minutes and using the 4500 6s 40C I have 35% left when I land. Perfect for what I want.

I happen to have my radio here with me. Throttle curve is below.

Spectrum DX9
1-0
2-30
3-50
4-63
5-74
6-85
7-100

Point 4 is 1/2 throttle stick; 63%throttle.

Hope this helps. Good luck.
Last edited by Pattern_is_fun; Dec 18, 2019 at 07:35 PM.
Dec 18, 2019, 09:59 PM
Registered User
Quote:
Originally Posted by Pattern_is_fun
Hey Andrew.

I too flew the Olympus for a few flights. I then went to the Angel 50 and then to the Mythos. I don’t know if the FMS 550kv will give you the ‘max’ Power to weight but trust me, it’s a great fit for the plane - keeping the wind loading very light. I posted throttle curves here somewhere which will be a good starting point. This assumes you will fly the horizontal speed at 1/2 throttle and EASE into any upline not pushing the throttle quickly. Strive for constant speed with the power off downline speed dictating the baseline horizontal speed. Run a 16x10e with the FMS ESC and the combo is great.

There are many more expensive motor / ESC combinations out there but in my 3 years flying competition with this motor combo you will not be disappointed. Take note I use one elevator servo located at the back of the canopy. This allows for a lighter motor (as well as less tail momentum in snaps) as I don’t have to compensate for rear servo weight. Be careful here. Plan accordingly.

I fly the masters sequence in 7 minutes and using the 4500 6s 40C I have 35% left when I land. Perfect for what I want.

I happen to have my radio here with me. Throttle curve is below.

Spectrum DX9
1-0
2-30
3-50
4-63
5-74
6-85
7-100

Point 4 is 1/2 throttle stick; 63%throttle.

Hope this helps. Good luck.
Thanks! I happened to find that Horizon listed the OLYMPUS as in stock. I thought it was discontinued. So I ordered one...I can harvest the power system directly!

What did you have to do to run 1 ele servo? Is it a lot of work?

I just received the Mythos tonight. I have not ordered servos. Do you know if there is a hi voltage low profile hitec servo for ailerons? I like to run life pack in my expensive models. Debating this time...life pack costs weight.
Dec 18, 2019, 11:08 PM
Registered User
Pattern_is_fun's Avatar
I used JR9411 for ailerons. Had them from past 2M planes. They are low profile. Elevator and rudder are JR $30 servos - DS821. Great centering, good speed. I use the BEC with the 6S Battery. Yes, I know, not the best idea but saves weight and I have 3 years of hard flying. Look back in posts on the elevator setup. It doesn’t take me long but I’ve done it several times. You won’t need HV servos as the 821 specs work great.

Specifications 9411
Modulation: Digital
Torque: 4.8V: 82.00 oz-in (5.90 kg-cm); 6.0V: 95.00 oz-in (6.84 kg-cm)
Speed: 4.8V: 0.15 sec/60°; 6.0V: 0.12 sec/60°
Weight: 1.36 oz (38.6 g)
Dimensions:
Length: 1.41 in (35.8 mm)
Width: 0.71 in (18.0 mm)
Height: 1.03 in (26.2 mm)
Motor Type: Coreless


Specifications; DS821
Modulation: Digital
Torque: 4.8V: 72.00 oz-in (5.18 kg-cm); 6.0V: 88.00 oz-in (6.34 kg-cm)
Speed: 4.8V: 0.19 sec/60°; 6.0V: 0.15 sec/60°
Weight: 1.50 oz (42.5 g)
Dimensions:
Length:1.50 in (38.1 mm)
Width:0.74 in (18.8 mm)
Height:1.47 in (37.3 mm)
Last edited by Pattern_is_fun; Dec 19, 2019 at 04:39 PM.
Dec 20, 2019, 12:28 PM
Registered User
Quote:
Originally Posted by Pattern_is_fun
I used JR9411 for ailerons. Had them from past 2M planes. They are low profile. Elevator and rudder are JR $30 servos - DS821. Great centering, good speed. I use the BEC with the 6S Battery. Yes, I know, not the best idea but saves weight and I have 3 years of hard flying. Look back in posts on the elevator setup. It doesn’t take me long but I’ve done it several times. You won’t need HV servos as the 821 specs work great.

Specifications 9411
Modulation: Digital
Torque: 4.8V: 82.00 oz-in (5.90 kg-cm); 6.0V: 95.00 oz-in (6.84 kg-cm)
Speed: 4.8V: 0.15 sec/60°; 6.0V: 0.12 sec/60°
Weight: 1.36 oz (38.6 g)
Dimensions:
Length: 1.41 in (35.8 mm)
Width: 0.71 in (18.0 mm)
Height: 1.03 in (26.2 mm)
Motor Type: Coreless


Specifications; DS821
Modulation: Digital
Torque: 4.8V: 72.00 oz-in (5.18 kg-cm); 6.0V: 88.00 oz-in (6.34 kg-cm)
Speed: 4.8V: 0.19 sec/60°; 6.0V: 0.15 sec/60°
Weight: 1.50 oz (42.5 g)
Dimensions:
Length:1.50 in (38.1 mm)
Width:0.74 in (18.8 mm)
Height:1.47 in (37.3 mm)
Thanks,

What do you think of 2 D-85Mg servos as the elevator servos? These only weigh 0.77 oz each and I have them already available (extras from another project). The make 60 in-oz torque at 6V so I would think more capable then the single 88 in-oz for the DS821.

Happy Holidays,

Andy
Dec 20, 2019, 01:00 PM
Registered User
Pattern_is_fun's Avatar
Hey Andy. Happy holidays to you too.

There are many options for servos. As we all know you’ll want servos with very little slop (in gears and deadband) as possible with linkages to match. If your putting 1.5oz in the tail you’ll have to compensate with motor weight and battery position. I’m sure this will be fine as many have done this in the past. My one 72oz-in servo does fine pushing both elevator halves so, while a bit of overkill, your on the safe side for sure.


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